1. Field of the Invention
The present invention relates to a nickel layer deposited by sputtering and having a reduced stress, and a process for depositing such a sputtered nickel layer.
2. Description of the Related Art
A consecutive sputtering of titanium, nickel and gold layers onto a semiconductor substrate or wafer to form a laminated metal electrode, in which an argon pressure used during the sputtering is usually 2 to 10 mTorr, is known. This pressure range is adopted because, at a higher argon pressure, the electric resistivity of the deposited layer is high and the load on a vacuum pump becomes higher as the argon pressure is increased.
Nevertheless, in the conventional sputtering, a high stress occurs in particularly the deposited nickel layer, thereby bending the semiconductor wafer and reducing the adhesive strength of the deposited layers. Particularly, the bending of a wafer is a severe problem in an automatic manufacturing line, and wafers having a bend larger than 350 .mu.m cannot be transferred in the automatic manufacturing line and thus must be manually transferred.